Your Yanmar owner's manual indicates the fuel filter should be replaced every 250 hours or once per year, whichever is sooner.

Applications include these engines (and the boats that we are aware used these engines... There could be other combinations as well):
• 4JH3-TE (Catalina 470)
• 4JH2-UTE (Catalina 50)

CAUTION: Always carry several spare fuel filters. Under normal circumstances you won't need them. But if you do need them it will be at the worst possible time and you will need them desperately! In heavy seas, any accumulation of debris in the bottom of the tank will get stirred up and mixed with the fuel. When you need the engine the most, the filter will become clogged with the debris, the engine will be starved for fuel, and it will die.

We carry these parts for your convenience though you may find them elsewhere less expensive due to the manufacturer's restricted distribution.